Michael is 4 times as old as brandon and is also 27 years older than brandon

M = 4*B
M + 27 = B
Substitute
M = 4*(M+27)
M = 4M + 108
subtract 4M from both sides
-3M = 108
Divide both sides by -3
M = -36

Now we substitute 
-36 + 27 =B 
-9 = B

Since people can't be negatively aged, we change the sign to positive

So Michael is 36 and Brandon is 9.

Hope this helps :)